dispatch.on()

dispatch.on(typenames[, callback])

Adds, removes or gets the callback for the specified typenames. If a callback function is specified, it is registered for the specified (fully-qualified) typenames. If a callback was already registered for the given typenames, the existing callback is removed before the new callback is added.

The specified typenames is a string, such as start or end.foo. The type may be optionally followed by a period (.) and a name; the optional name allows multiple callbacks to be registered to receive events of the same type, such as start.foo and start.bar. To specify multiple typenames, separate typenames with spaces, such as start end or start.foo start.bar.

To remove all callbacks for a given name foo, say dispatch.on(".foo", null).

If callback is not specified, returns the current callback for the specified typenames, if any. If multiple typenames are specified, the first matching callback is returned.